Electronics Forum | Fri Mar 16 02:20:09 EDT 2007 | Wayne
Have to check with paste manufacturer. paste on the stencil should be at least 12 hours paste on the board before mounting should be at least 4 hours.
Electronics Forum | Mon Mar 19 14:24:30 EDT 2007 | jdengler
I have been involved with the evaluation of close to a dozen pastes from 5 manufactures. I never found one that would rest on a board for anything close to 24 hrs and still have acceptable performance. Jerry
Electronics Forum | Thu Aug 10 11:32:34 EDT 2017 | dleeper
You could always take a scrap board, paste it, and let it sit out over night. Reflow it and then you should have a nice visual aid, covered in solder balls and grainy, irregularly shaped solder mounds.
Electronics Forum | Mon Mar 19 10:35:44 EDT 2007 | dyoungquist
We use a no-clean lead free paste with our manufacturing floor temp 70-75F and humidity 20%-30%. We have found that if the time from pasting a board until it goes into our reflow oven is less than 4 hours we have no problems. If it is greater than
Electronics Forum | Thu Mar 29 08:58:06 EDT 2007 | chrissieneale
Started measuring rework last week - on some of the boards we are looking at a shocking 20% right first time yield. The paste thing has to be fixed as it's being left more than four hours. Thanks for all the comments - Will let everyone know the re
Electronics Forum | Thu Mar 29 09:11:23 EDT 2007 | slthomas
chrissie, at my last place of employment the reason they did it was so they could print the last of a lot, then change over the printer and start printing up for the next lot and have some ready to go when they finished changing over the chip shooter
Electronics Forum | Thu May 23 12:20:08 EDT 2002 | cyber_wolf
Well it depends on what kind of oven you have. If you have a short oven, you are going to have a difficult time. You will probably end up having several different profiles if that is the case. We have 3 BTU TRS 212 furnaces. They are fairly long 8 zo
Electronics Forum | Tue Apr 03 13:10:15 EDT 2007 | slthomas
Personally I wouldn't count anything but minutes. You need to know how long it takes to perform each task in order to balance your line. What I'm gathering is that you've got one printer feeding 4 machines, all running different jobs or maybe a pai
Electronics Forum | Fri Nov 09 11:22:43 EST 2001 | denis
We are a contract manufacturer and we do business with a big company. There is a mistake in the design of the PCBs they are supplying: the pads are too long (under the component) and sometimes we get short circuit we cannot see. Changing the design w
Electronics Forum | Thu Oct 11 17:32:59 EDT 2007 | wayne123
In Block repeat information did you put the rotation in before optomizing? This is where the machine gets the rotation of these individual boards. The Block fiducials are good to use, but they aren't for defining rotation. If you optomized using note
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